Unify pseudo state save method "none" (stateless) with modes "server" and "client"

In JSF the user can choose to save state on the server or the client via the javax.faces.STATE_SAVING_METHOD context parameter. This is a global setting that applies to all views (URLs) in the application.

At the same time there's effectively a "none" setting, which is what happens when a view root (e.g. via the f:view tag) is set to transient. This is also called "stateless".

I'd like to propose that in addition to the current mechanism used to set a single view to stateless, the range of values for javax.faces.STATE_SAVING_METHOD context parameter is extended with a "none" option.

The intended purpose of this option is to globally set all views in the application to stateless.

The issue does not name implementation files or tests. Start by tracing how javax.faces.STATE_SAVING_METHOD is processed and how transient view roots are handled, then identify the tests covering server, client, and stateless behavior. Done means a globally configured "none" option consistently makes all views stateless.

Written by the indexing model from the issue text.